Use a direct include of the message_loop header in ppapi/, printing/, rlz/, sync/.

ppapi/proxy/ppb_message_loop_proxy.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_
 #define PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/message_loop.h"
+#include "base/message_loop/message_loop.h"
 #include "ppapi/proxy/interface_proxy.h"
 #include "ppapi/proxy/ppapi_proxy_export.h"
 #include "ppapi/shared_impl/ppb_message_loop_shared.h"
 #include "ppapi/thunk/ppb_message_loop_api.h"
 
 struct PPB_MessageLoop_1_0;
 
 namespace ppapi {
 namespace proxy {
 
@@ skipping 79 matching lines @@
   static const PPB_MessageLoop_1_0* GetInterface();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PPB_MessageLoop_Proxy);
 };
 
 }  // namespace proxy
 }  // namespace ppapi
 
 #endif  // PPAPI_PROXY_PPB_MESSAGE_LOOP_PROXY_H_